 <template>
  <div>
    <router-link
      tag="div"
      to="/"
      class="header-abs"
      v-show="showAbs"
    >
      <span class="iconfont icon-fanhui header-abs-back"></span>
    </router-link>
    <div
      class="header-fixed"
      v-show="!showAbs"
      :style="opacityStyle"
    >
      <span class="iconfont icon-fanhui header-fixed-back"></span>
      景点详情
    </div>
  </div>
</template>

<script>
    export default {
      name: 'DetailHeader',
      data (){
        return{
          showAbs:true,
          opacityStyle:{
            opacity:0
          }
        }
      },
      methods:{
        handleScroll (){
          const top = document.documentElement.scrollTop
          if(top > 60){
            let opacity = top/140
            opacity = opacity>1?1:opacity
            this.opacityStyle={
              opacity
            }
            this.showAbs = false
          }else{
            this.showAbs = true
          }
        }
      },
      activated (){
        window.addEventListener('scroll',this.handleScroll)
      },
      deactivated (){
        window.removeEventListener('scroll', this.handleScroll)
      },
    }
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position: absolute
    left: .2rem
    top: .2rem
    width: .8rem
    height: .8rem
    line-height: .8rem
    border-radius: .4rem
    text-align: center
    background: rgba(0, 0, 0, .8)
    .header-abs-back
      color: #fff
      font-size: .4rem
  .header-fixed
    z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #fff
    background: $bgColor
    font-size: .32rem
    .header-fixed-back
      position: absolute
      top: 0
      left: 0
      width: .64rem
      text-align: center
      font-size: .4rem
      color: #fff
</style>
